The present invention relates to a non-contact data carrier and a method of fabricating the same.
A non-contact data carrier is provided with a memory capable of storing various data and is capable of non-contact communication with external reader/writer. Non-contact data carriers are used for automatic package sorting, inventory control, commodity protection from theft, production management and distribution management.
Such a non-contact data carrier is fabricated by the following procedure. An antenna pattern is formed by etching a metal foil, such as an aluminum foil, laminated to a substrate of a resin through a resist pattern. Then, a jumping circuit is formed by forming conductive members on the back surface of the substrate and connecting the antenna pattern through through holes to the conductive members. An IC chip provided with bumps is located such that the bumps correspond to antenna connecting terminals, and the bumps are electrically connected to the antenna connecting terminals. Then, the antenna pattern and the IC chip are covered with a protective coating.
In fabricating this non-contact data carrier, the jumping circuit must be formed by connecting the antenna pattern and the conductive members through the through holes, the IC chip provided with the bumps must be located relative to the antenna connecting terminals, and the bumps formed on the back surface of the IC chip must be electrically connected to the antenna connecting terminals. Since the antenna pattern and the IC chip are separately manufactured, the cost of the non-contact data carrier is high.
Thus, the manufacturing cost of non-contact data carriers is high. Although dependent on configuration, it is said that non-contact data carriers using a microwave of the 2.45 GHz frequency band cost 5 to 100 odd dollars (xe2x80x9cMicro Stamp presented by Mitsui and Co., Ltd. http://www.mbd.co.ip/mc/rfid.00.htmlxe2x80x9d).
It is an object of the present invention to provide a non-contact data carrier capable of being fabricated at a manufacturing cost lower than that of the conventional non-contact data carriers, and a method of fabricating the non-contact data carrier.
According to one aspect of the present invention, a non-contact data carrier comprises: a semiconductor device; a coil antenna having opposite ends; wires connecting the semiconductor device and the opposite ends of the coil antenna; and a sealing resin coating encapsulating the semiconductor device, the coil antenna and the wires therein.
In the non-contact data carrier according to the present invention, the semiconductor device is mounted on a semiconductor device mount substantially provided on the same plane as that of the coil antenna.
In the non-contact data carrier according to the present invention, a protective layer is formed on surfaces of the coil antenna and the semiconductor device mount opposite to the side of the sealing resin coating.
According to another aspect of the present invention, a non-contact data carrier fabricating method comprises the steps of: preparing a conductive substrate; forming a first resist pattern layer provided with openings on one of the surfaces of the conductive substrate, and forming a second resist pattern layer provided with openings on the other surface of the conductive substrate; forming locating holes in the substrate by coating the first resist pattern layer with a protective film and etching the conductive substrate through the openings of the second resist pattern layer; forming a coil antenna having opposite ends, and a semiconductor device mount by removing the protective film from the first resist pattern layer and plating the conductive substrate through the openings of the first resist pattern layer; removing the first and the second resist pattern layer from the conductive substrate; fixedly mounting a semiconductor device on the semiconductor device mount and connecting the opposite ends of the coil antenna to the semiconductor device; encapsulating the semiconductor device, the coil antenna, the wires and the surroundings of the semiconductor device mount with a sealing resin coating; and removing the conductive substrate from the semiconductor device mount and the coil antenna.
In the non-contact data carrier fabricating method according to the present invention, one of the surfaces of the conductive substrate is roughened by a sandblasting process to form irregularities therein before forming the fist resist pattern layer.
In the non-contact data carrier fabricating method according to the present invention, an oxide film is formed on the roughened surface of the conductive substrate by using an oxidizing solution.
In the non-contact data carrier fabricating method according to the present invention, a protective layer is formed on the surfaces of the coil antenna and the semiconductor device mount opposite to the side of the sealing resin coating after removing the conductive substrate from the semiconductor device mount and the coil antenna.
In the non-contact data carrier fabricating method according to the present invention, a plurality of semiconductor devices and a plurality of coil antennas respectively corresponding to the semiconductor devices are formed on the conductive substrate, and the sealing resin coating is cut and divided into divisions, each including one of the semiconductor devices and the coil antenna corresponding to the semiconductor device after removing the conductive substrate from the semiconductor mounts and the coil antennas.
The non-contact data carrier does not need any work for forming the jumping circuit by connecting the antenna pattern to the conductive member through the through holes, locating the IC chip with its bumps coincided with the antenna connecting terminals or electrically connecting the bumps to the antenna connecting terminals. Since the non-contact data carrier can be fabricated by steps of simply placing the semiconductor device on the semiconductor device mount and connecting the semiconductor device to the coil antenna by the wires, the non-contact data carrier of the present invention can be manufactured at a low cost.
Although the non-contact data carrier of the present invention is small and has a short communication distance, the communication distance can be extended by providing a label or a card of a tag body with a booster antenna when the non-contact data carrier is used as a tag.
An antenna pattern having a proper inductance may be formed on the surface of the sealing resin coating or the protective layer or on both the surfaces of the sealing resin coating and the protective layer, and the antenna pattern may be used as a component of a booster antenna or a resonance circuit. When such an antenna pattern is used, the antennal pattern may be electrically connected through via holes or through holes to the coil antenna so that the antenna pattern may resonate with the coil antenna. An additional antenna may be formed without forming any via holes or through holes, a proper pattern may be formed on the antenna, and an insulating layer, such as the sealing resin coating or the protective layer, may be used as a component of capacitor, and those may be used for resonation.